It's good that he sees he needs to change his behavior. I think someone else mentioned it's a process, so you'll have to work with him, give him a chance to get himself under control. Maybe he needs an outlet, like you have PC, to voice the things that are bothering him before he vents it all at you?

Like calming down before you two talk about something, maybe he does something to let himself have his anger first, so that it's not directed at you, and then he can calmly talk to you about it? It's okay for him to feel anger, he just has to process it properly and not blow it all at you and expect you to deal with it for him,